1. Field of the Invention
The present general inventive concept relates to a speaker to convert an electrical signal into sound.
2. Description of the Related Art
Usual speakers convert an electrical signal into an acoustic signal by Fleming's right hand rule which shows the direction of induced current flow when a conductor moves in a magnetic field. The general operation of a speaker is disclosed in Korean Patent Application No. 10-2005-0020540 filed on Mar. 11, 2005 by the same inventor.
Such a speaker uses a cone paper as a conversion element to convert mechanical energy into acoustical energy. The cone paper receives vibration of a voice coil, and thus causes air pressure to be changed. By doing so, the cone paper affects approximately 90% or more of the sound quality, and different sounds may be produced according to material properties, fabrication parameters, structural geometry (shape), and so on.
Generally, to fabricate a cone paper, pulp is most widely used since it is cheap, enables sound to be adjusted easily, and it is easy to make shape. And polypropylene which makes the appearance more beautiful and more tolerant to shock may also be used.
The cone paper made of pulp may be formed with various materials, and thus the pulp is advantageous in terms of producing various sounds. However, if the cone paper is externally exposed, its appearance is not good and is fragile against shock impact.
The cone paper made of polypropylene may be formed in various shapes, and thus the polypropylene is advantageous in terms of providing better appearance and is more shock-resistant. However, polypropylene is restrictively used for a specific speaker since the speaker made of polypropylene produces relatively dead sound compared to the cone paper made of pulp due to the problem caused by the material or the method for forming appearance.